I had noted the variances in powder charges between the Lott and .458 Win immediately on purchasing Hornady's 7th Edition, sometime before I read Ross's article on the same.
I had checked with one of the top (or the top) ballistics' guy, when Hornady was doing renovations, and asked questions about the difference in case volume between their Win and Lott cases. He scrambled a bit to find the data (due to renovations), and when located these numbers were given to me: 94.2 for the .458 Win and 102.6 for the Lott. That's nothing like Ross' claim, and it explained to me why so little difference between the two with equal length barrels. Also, keeping in mind the higher psi for the Lott by SAAMI. Then he also gave the "freebore" or leade distinctions using the same 500gr. For the WIN it was over .7 and the Lott something under .2. So there's little mystery left as to why the .458 WIN can match the Lott, or exceed it, when the heavies are seated longer than the Lott at less pressure.
All that, of course, you've pointed out several times. But I thought some would like to know the real distinctions in water capacity between the two HORNADY cases, which is only 8.4 grs water, or 7 grains of the same powder when the same bullet is seated to the same depth. Of course, one doesn't NEED to seat bullets to 1/2" in the WIN. 1/4" will suffice in the Ruger No.1 or M70 and CZ 550 with a lightly compressed powder charges and a LEE crimp die (especially if a cannelure tool is used, as in your suggestion).
Then, as Ross alluded to, in some loads with the same powder, there's virtually no distinction in charge and results; except that the .458 Win is doing it at 59,500 psi and the Lott at 62,000 Examples: IMR 4320 and IMR 4064.
ANYONE, with less than a high school diploma can clearly see the math - IF THEY WANT TO!
Another thing: Even the LOTT that Jack built with the .458 Win throat, couldn't exceed the COL of a .458 WIN with an action that allows it! They would be the same, except the .458 that "Jack built" was a wildcat without limits in PSI (or until something broke!). There's no doubt now that the folk at Winchester knew what they were doing when the original .458 Winchester Magnum was brought out in 1956.
